Power control was first used in IS-95 (see EIA/TIA-95 Rev A, “Mobile station-base station compatibility standard for dual-mode wideband spread spectrum cellular system”, 1995) and then in CDMA-2000 for voice services. The main purpose was to balance the received power to be close to a constant level, resulting in a consistent voice quality.
In data communications, instead of power control, rate control techniques have been employed, for example, in high speed down-link packet access (HSDPA). See Physical Layer Standard for cdma2000 Spread Spectrum Systems, TR45.5.3.1, Jun. 14-18, 1999. With rate control techniques, a fixed transmit power is used, but more or less aggressive coding and/or modulation order is employed.